As well known in the art, artificial limbs are man-made devices that are fabricated such that their appearance or function can replace that of a missing part of an arm or a leg. Some types of artificial limbs have the same shape and function as those of a missing joint. Although there are several categories of artificial limbs depending on the purpose and parts to be used, they are generally divided into an upper artificial limb that is commonly referred to as an artificial arm and a lower artificial limb that is commonly referred to as an artificial leg.
In order to use an artificial limb, first, a socket liner is worn on a stump of a wearer, and the artificial limb is then connected to the socket liner. Most devices for connecting the artificial limb to the socket liner in the related art use a pin lock, which fixes the artificial limb and the socket liner using a pin. The pin lock is a type of locking mechanism in which the socket liner is connected to the artificial limb by fixing a metal pin to the distal connecting end of the socket liner. In the case of the pin lock, the area where the stump of the wearer and the artificial limb are connected to each other is only the cross-sectional area of the pin. Consequently, it is difficult to balance the weight of the body in the standing position, and a gap in a fastening portion causes noises when walking.
FIG. 11 is a view showing a fastening structure of an artificial limb structure having a conventional pin lock device. As shown in the figure, the pin lock has a long connecting portion where the stump of the wearer and the artificial limb are connected to each other. This structure, however, is difficult to use if the stump of the wearer is long. In addition, since the area where the artificial limb and the socket liner are connected is small, high pressure is applied to the stump of the wearer when walking, which may cause abrasion and the like, and it is difficult to precisely align and attach the artificial limb to the hole of the pin lock.
In the case of Korean Patent No. 10-1102615 filed and patented by the applicant of the present invention, a magnetic lock device including an electro-permanent magnet composed of a permanent magnet and an electromagnet is used in an artificial limb structure, so the artificial limb and the socket liner can be easily attached to and detached from each other. However, the magnetic lock device still has the inconvenience of requiring power to be supplied thereto.